Chemically Competent E. Coli

Notes:

You need fresh cells.

Often people inoculate a few mL of the culture for overnight growth, then use 200 uL to inoculate the ~50 mL of culture they will make competent.

Some people in our lab believe you want to start with a fresh plate and don't even use one that is a few days old. Other people (Mila) are mostly concerned about the OD being right at the time of harvest.

You need to flash freeze the cells at the end of the procedure. You can do this by pouring liquid nitrogen over them, or you can freeze your tubes at -80oC the night before, put your aliquots in, and stick them back at -80oC.